KR20040002660A - Method for producing cyclohexanone oxime - Google Patents

Abstract

PURPOSE: A method for preparing a cyclohexanone oxime is provided, to produce a cyclohexanone oxime in a high yield by suppressing the deterioration of the catalytic activity of titanosilicate as a catalyst. CONSTITUTION: The method comprises the step of reacting cyclohexanone with hydrogen peroxide and ammonia in the presence of titanosilicate and a silicon compound other than titanosilicate. Preferably the silicon compound other than titanosilicate is at least one selected from the group consisting of silica gel, silicic acid., silicate and zeolite. Preferably the amounts of titanosilicate and a silicon compound are about 0.1-10 wt% based on the liquid part of the reaction mixture, respectively; and the reaction is carried out in the presence of about 10 wt% or more of water based on the reaction mixture.

Description

Method for preparing cyclohexanone oxime {METHOD FOR PRODUCING CYCLOHEXANONE OXIME}

The present invention relates to a process for preparing cyclohexanone oxime from cyclohexanone using ammonia and hydrogen peroxide. Cyclohexanone oxime is useful as a starting material for the preparation of ε-caprolactam and the like.

For the preparation of cyclohexanone oximes, a method of reacting cyclohexanone with hydrogen peroxide and ammonia in the presence of a titanium silicate catalyst has been proposed (e.g., Japan corresponding to US Pat. No. 4,745,221). Patent Application Publication (JP-A-) 62-59256; Japanese Patent Application Publication No. JP-A-6-49015, corresponding to US Patent No. US-5,312,987; Japanese Patent Application Publication No. US-5,227,525 Patent Application Publication Nos. JP-A-6-92922; and Japanese Patent Application Publication Nos. JP-A-7-100387 corresponding to US Pat. Nos. 5,683,952, US-5,691,266 and US-5,874,596) . While conventional processes for the preparation of cyclohexanone oximes carry out neutralization with hydroxylamine sulfate, the process does not require neutralization of sulfuric acid with ammonia, and the use of solid catalysts facilitates separation of the product from the catalyst. It is advantageous in that it can be performed.

However, in the above reaction of cyclohexanone with hydrogen peroxide and ammonia, the catalytic activity of the titanium silicate catalyst gradually decreases as the reaction time elapses, and the conversion rate of cyclohexanone may become insufficient.

One of the objects of the present invention is to provide a method for producing a high yield of cyclohexanone oxime by inhibiting the inactivation of titanium silicate in the reaction of cyclohexanone with hydrogen peroxide and ammonia.

As a result of the intensive studies of the present inventors, it has been found that the above and other objects can be achieved by reacting cyclohexanone with silicon compounds other than titanium silicate in the presence of titanium silicate, and the present invention has been completed.

The present invention provides a method for preparing cyclohexanone oxime, comprising reacting cyclohexanone with hydrogen peroxide and ammonia in the presence of titanium silicate and silicon compounds other than titanium silicate.

In the present invention, cyclohexanone oxime is prepared by ammonia oxidation of cyclohexanone, wherein cyclohexanone is reacted with hydrogen peroxide and ammonia in the presence of silicon compounds other than titanium silicate and titanium silicate.

The titanium silicate used in the present invention may be a zeolite comprising titanium, silicon and oxygen as elements in its skeletal structure. Titanium silicates may have a framework structure substantially composed of titanium, silicon and oxygen, or any other elements as well as these elements. Titanium silicates may have an atomic ratio of silicon to titanium of 10 to 1000, and may be in the form of fine powders, pellets and the like. Titanium silicate may be prepared by the method disclosed in Japanese Patent No. JP-A-56-96720 corresponding to US Pat. No. 4,410,501 and the like.

In the present invention, by using a silicon compound other than the titanium silicate and the titanium silicate, cyclohexanone is reacted with hydrogen peroxide and ammonia to obtain cyclohexanone oxime.

Cyclohexanone used as the starting material in the present invention can be obtained, for example, by oxidizing cyclohexane, hydrating cyclohexene, followed by dehydrogenation, or hydrogenation of phenol.

Hydrogen peroxide used in the present invention can be prepared by the so-called anthraquinone method. The anthraquinone method is, for example, dissolving α-ethylanthraquinone in a non-aqueous solvent such as benzene, followed by catalytic hydrogenation to obtain hydroanthraquinone, while oxidizing hydroanthraquinone to α-ethylanthraquinone, It may be carried out by a method for providing hydrogen peroxide. Commercial hydrogen peroxide, an aqueous solution having a concentration of about 10% to about 70% by weight, can also be used in the present invention. The relative molar amount of hydrogen peroxide is preferably in the range of about 0.5 moles to about 3 moles, more preferably in the range of about 0.5 moles to about 1.5 moles, based on 1 mole of cyclohexanone. Hydrogen peroxide used in the present invention includes, for example, phosphate salts such as sodium phosphate, polyphosphate salts such as sodium pyrophosphate and sodium tripolyphosphate, pyrophosphoric acid, ascorbic acid, ethylenediamine-tetraacetic acid, nitro tri-acetic acid, Stabilizers including amino tri-acetic acid, diethylenetriamino penta-acetic acid, and the like.

In the present invention, ammonia can be used in a gaseous state, a liquid state, or a solution state using water, an organic solvent, or the like. The relative molar amount of ammonia is preferably about 1 mole or more, more preferably about 1.5 mole or more, based on 1 mole of cyclohexanone.

The reaction for preparing cyclohexanone oxime using ammonia and hydrogen peroxide can be carried out in solution using a solvent. Examples of solvents include alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol and tert-amyl alcohol, water, and mixtures thereof. do.

In the present invention, the reaction for preparing cyclohexanone oxime using ammonia and hydrogen peroxide is carried out together with silicon compounds other than titanium silicate in the presence of titanium silicate. (Hereinafter, silicon compounds other than titanium silicates may in some cases be referred to simply as “silicon compounds”.) By using silicon compounds in combination with titanium silicates, it is possible to inhibit the inactivation of titanium silicates, and thereby in the reaction. The amount of titanium silicate used as catalyst can be reduced. In terms of cost reduction, it is usually desirable to use silicon compounds which are less expensive than relatively expensive titanium silicates. The silicon compound, by itself, may be substantially free of catalytic activity in the reaction.

Examples of silicon compounds include silicon and oxygen containing compounds such as silica gel, silicic acid and silicates. It is also preferable to use crystalline silica gels and metallo-silicates, each having a zeolitic structure. The silicon compound may be used alone or in combination of two or more silicon compounds, if necessary.

In the present invention, it is preferred to use titanium silicate and silicon compounds in concentrations of about 0.1% to about 10% by weight, respectively, based on the liquid portion of the reaction mixture, so that the titanium silicate and silicon compounds are incorporated into the mixture. Suspended.

The effect of inhibiting inactivation of the catalytic activity of titanium silicates is particularly pronounced when water is present in the reaction mixture at a concentration of at least about 10% by weight.

The reaction for preparing cyclohexanone oxime with ammonia and hydrogen peroxide can be carried out in batch mode or in continuous mode. The batch mode reaction can be carried out by, for example, charging the reactor with cyclohexanone, ammonia, titanium silicate, silicon compound and solvent and introducing hydrogen peroxide with stirring therein; Or by charging the reactor with cyclohexanone, titanium silicate, silicon compound and solvent and introducing hydrogen peroxide and ammonia with stirring therein; Or by charging the reactor with titanium silicate, silicon compound and solvent and introducing cyclohexanone, hydrogen peroxide and ammonia with stirring therein. The continuous reaction is carried out by the process of extracting the liquid portion of the resulting reaction mixture from the reactor through a filter, for example, while preparing a suspension of titanium silicate and silicon compounds in a reactor in which cyclohexanone, hydrogen peroxide, ammonia and a solvent are additionally introduced. Can be performed. From the viewpoint of preventing decomposition of hydrogen peroxide, it is preferable to use a glass lining reactor, a stainless steel reactor, or the like.

The reaction temperature may range from about 50 ° C to 100 ° C. The reaction can be carried out at standard pressure, and a pressure for increasing the solubility of the ammonia into the liquid portion of the reaction mixture is preferred. For reactions under pressure, inert gases such as nitrogen gas and helium gas can be used to adjust the pressure.

Post-processing procedures, such as the separation of cyclohexanone oxime from the reaction mixture, are not limited and may be appropriately carried out using known methods. For example, the separation of cyclohexanone oxime can be carried out in such a way that the titanium silicate and silicon compound are separated from the reaction mixture by filtration or the like to obtain a liquid portion of the reaction mixture and then distill the liquid portion. .

According to the present invention, cyclohexanone is reacted with hydrogen peroxide and ammonia while suppressing the inactivation of titanium silicate as a catalyst to produce a high yield of cyclohexanone oxime.

As the present invention has been described above, it will be apparent that the same invention can be modified in many ways. Such modifications are considered to be within the spirit and scope of the invention, and all such modifications apparent to those skilled in the art will be within the scope of the following claims.

The entire disclosure of Japanese Patent Application No. 2002-189450, filed on June 28, 2002, indicating the specification, claims, and abstract, is hereby incorporated by reference in its entirety.

Example

The invention is described in more detail with reference to the following examples, which should not be construed as limiting the scope of the invention.

In the examples and comparative examples, cyclohexanone and cyclohexanone oxime were analyzed by gas-chromatography, the conversion of cyclohexanone, selectivity for cyclohexanone oxime, and yield of cyclohexanone oxime based on the analysis results. Calculated as

Example 1

A 1 l autoclave as a reactor was charged with cyclohexanone, hydrous t-butyl alcohol (containing 12 wt% water) and 60 wt% hydrogen peroxide at rates of 67 g / hour, 252 g / hour and 43 g / hour, respectively. . At the same time, the ammonia was fed to the reactor to be present at a concentration of 2% by weight, based on the liquid part of the resulting reaction mixture, while the liquid part of the reaction mixture was withdrawn from the reactor through a filter, and the reaction was carried out continuously. During the reaction, titanium silicate and silica gel (trade name: WAKO GEL LP-20, manufactured by Wako Pure Chemical Industries, Ltd.) were added to the reactor in amounts of 0.9% and 6% by weight, respectively, based on the liquid portion of the reaction mixture. Put in. The continuous reaction was carried out with a residence time of 72 minutes under a temperature of 85 ° C. and a pressure of 0.25 MPa. As a result of analysis of the liquid portion obtained after the reaction of 5.5 hours, the conversion rate of cyclohexanone was 99.1%, the selectivity to cyclohexanone oxime was 99.5%, and the yield of cyclohexanone oxime was 98.6%.

Comparative Example 1

The amount of titanium silicate was changed from 0.9% to 1.3% by weight based on the liquid portion of the reaction mixture and a continuous reaction was carried out in the same manner as in Example 1 except that no silica gel was used. As a result, the conversion of cyclohexanone was 98.6%, the selectivity to cyclohexanone oxime was 99.5%, and the yield of cyclohexanone oxime was 98.1%.

Although the amount of titanium silicate used in Comparative Example 1 was higher than that in Example 1 (the amounts are 1.3% and 0.9% by weight, respectively, based on the liquid portion of the reaction mixture), silica gel was used in Comparative Example 1 Since not used, the conversion rate of cyclohexanone in Comparative Example 1 was found to be about the same or less than the conversion rate in Example 1.

Comparative Example 2

The amount of titanium silicate was changed from 0.9% to 1.2% by weight based on the liquid portion of the reaction mixture, and the continuous reaction was carried out in the same manner as in Example 1 except that no silica gel was used. As a result, the conversion of cyclohexanone was 93.0%, the selectivity to cyclohexanone oxime was 99.0%, and the yield of cyclohexanone oxime was 92.1%.

Although the amount of titanium silicate used in Comparative Example 2 was higher than that in Example 1 (the amount is 1.2% by weight and 0.9% by weight, respectively, based on the liquid portion of the reaction mixture), silica gel was used in Comparative Example 2 Since not used, the conversion rate of cyclohexanone in Comparative Example 2 was found to be about 6% by weight less than the conversion rate in Example 1.

Example 2

With stirring, at a temperature of 80 ° C., cyclohexanone (12.8 g), 25% by weight aqueous ammonia (13.2 g), hydrous t-butyl alcohol (19.7 g) (water) in a 200 ml autoclave (made from SUS316) as a reactor 13 wt%), titanium silicate (1 g) and silicic acid (3 g) (manufactured by Nakalai Chemicals Co., Ltd.) were charged. 30% hydrogen peroxide (14.9 g) was fed to the reactor over 55 minutes and the resulting reaction mixture was maintained for 35 minutes. The catalyst was separated from the reaction mixture and the residual liquid portion was analyzed. As a result, the conversion of cyclohexanone was 70.9%, the selectivity to cyclohexanone oxime was 74.4%, and the yield of cyclohexanone oxime was 52.7%.

Comparative Example 3

The reaction was carried out in the same manner as in Example 2 except that no silicic acid was used. As a result, the conversion of cyclohexanone was 68.0%, the selectivity to cyclohexanone oxime was 70.6%, and the yield of cyclohexanone oxime was 48.0%.

Example 3

A continuous reaction was carried out in the same manner as in Example 1, except that the amount of titanium silicate was changed from 0.9% to 1% by weight based on the liquid portion of the reaction mixture. Until the reaction time had elapsed 16 hours, no increase in oxygen concentration in the gaseous portion due to deactivation of the catalyst was observed. As a result of analysis of the liquid portion obtained after the reaction of 15.5 hours, the conversion rate of cyclohexanone was 85.3%, the selectivity to cyclohexanone oxime was 96.7%, and the yield of cyclohexanone oxime was 82.5%.

Comparative Example 4

The amount of titanium silicate was changed from 0.9% to 1% by weight based on the liquid portion of the reaction mixture, and the continuous reaction was carried out in the same manner as in Example 1 except that no silica gel was used. When the reaction time passed 6 hours, an increase in the oxygen concentration in the gaseous portion due to deactivation of the catalyst was observed. As a result of analysis of the liquid portion obtained after the reaction of 5.5 hours, the conversion rate of cyclohexanone was 87.6%, the selectivity to cyclohexanone oxime was 90.4%, and the yield of cyclohexanone oxime was 79.3%.

According to the present invention, a high yield of cyclohexanone oxime is provided by carrying out the reaction by inhibiting inactivation of titanium silicate as a catalyst.

Claims (4)

A method for preparing cyclohexanone oxime comprising reacting cyclohexanone with hydrogen peroxide and ammonia in the presence of titanium silicate and silicon compounds other than titanium silicate. The method of claim 1, wherein the silicon compound other than titanium silicate is at least one compound selected from silica gel, silicic acid, silicate and zeolite. The method of claim 1, wherein the titanium silicate and the silicon compound are used at concentrations of about 0.1% to about 10% by weight, respectively, based on the liquid portion of the reaction mixture. The process according to claim 1, wherein the reaction is carried out in the presence of an amount of water of at least about 10% by weight, based on the reaction mixture.